I want to play the campaign online so I go to play online and games and lobbies come up but not nearly as much as I would expect. Also I have created my own lobbies and it often takes very long for ppl to join. Steam says about 20,000 ppl are playing this game so were are all the servers? I tried using ~openserverbrower and I see a lot but its not very user friendly and I cant tell what servers are modded and not. Also im a new pc gamer/ steam user so sorry this is probably a noob question...

You're not seeing servers on the L4D game search, you're seeing local games (controlled by the download region that Steam Client is set to) with open slots that you can join in on (full games won't be listed, nether are Friend Only games).

To see the servers type openserverbrowser on the developer's console and go to the custom tab. Problem is that you have zero control of what to play other than what is already cued, because that browser was never meant to be used for L4D, it's just a left over from the Source Engine. As to what won't be modded, Valve servers and Pinion White servers, will never be modded, anything else is hit or miss. (Best Available is also hit or miss.)